In recent years, electric apparatus and electronic apparatus have been rapidly downsized with higher performance. Along with that, demands for downsizing electronic component with a larger capacity and higher reliability used for such apparatuses have been increased. A ceramic capacitor as one example of electronic components is not exception of this.
As for one of the measures for fulfilling such demands, it has been considered to make permittivity of dielectric material higher. Currently, as for barium titanate which is widely used as dielectric material showing the high permittivity, the barium titanate having perovskite type crystal structure (tetragonal form, cubic form) is the mainstream, which shows about several thousands of specific permittivity at room temperature. On the other hand, barium titanate having hexagonal structure (hexagonal barium titanate) was not much used as a dielectric material, because permittivity (about 400) thereof is lower than that of the perovskite type barium titanate in using temperature range.
However, Patent Documents 1 and 2 disclose that hexagonal bariumtitanate (h-BaTiO3) to which oxygen vacancy is introduced by using containerless solidification method shows extremely high specific permittivity which is 100000 or more at room temperature.
However, it has been difficult to control oxygen vacancy amount, because it is necessary to set the reducing atmosphere strictly. Also, it is considered that the oxygen vacancy itself is one of the factors to deteriorate lifetime, therefore it has been considered as difficult to use electronic components stably in which the oxygen-deficient hexagonal barium titanate is used.
Further, in the case of applying such the dielectric material having high specific permittivity to electronic components such as a ceramic capacitor and the like, annealing (reoxidazing) treatment is necessary. However, when the annealing treatment is performed to the above mentioned oxygen-deficient hexagonal barium titanate, oxygen is replenished, as a result, there was a problem that the specific permittivity has rapidly decreased in extremely short time.    Patent Document 1: Japanese Patent No. 3941871    Patent Document 2: Japanese Patent No. 4013226